In many areas of engineering, accurate measurement of a time interval is useful. For example, accurate measurement of a time interval is used in a phase detector of a digital phase locked loop (PLL). In addition, accurate measurement of a time interval is used in analog-to-digital converters and in high-resolution measuring equipment.
Often, time-to-digital converters (TDC) are used in order to perform accurate measurement of a time interval. After a time interval has been measured by a time-to-digital converter, it is necessary to wait a certain time until the time-to-digital converter is ready for a fresh measurement. This time is referred to as dead time for a time-to-digital converter. In order to allow measurement of time intervals without dead time, it is possible to alternatively use two time-to-digital converters which are connected in parallel. This is called time interleaving. The arrangement has the associated drawback that a mismatch in the two parallel-connected time-to-digital converters, which is caused by process variations, for example, results in the occurrence of a periodically occurring conversion error. In addition, such an arrangement takes up a large surface area. Therefore, a need exists for a method and system for improved time interval conversions.